Norma

Designation: C 802 – 96 (Reapproved 2002)

Standard Practice for

Conducting an Interlaboratory Test Program to Determine the Precision of Test Methods for Construction Materials1
This standard is issued under the fixed designation C 802; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number inparentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

1. Scope 1.1 This practice describes techniques for planning, conducting, and analyzing the results of an interlaboratory study of a test method. It is designed to be used in conjunction with Practice C 670. Thus, the procedures recommended in thispractice have the limited purpose of providing reliable information on which precision statements of the type described in Practice C 670 can be based. It is not appropriate for use in programs whose purpose is to develop a test method or to assess the relative merits of two or more test methods. 2. Referenced Documents 2.1 ASTM Standards: C 109/C109M Test Method for Compressive Strength ofHydraulic Cement Mortars (Using 2-in. or 50-mm Cube Specimens)2 C 136 Test Method for Sieve Analysis of Fine and Coarse Aggregates3 C 670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials3 C 1067 Practice for Conducting a Ruggedness or Screening Program for Test Methods for Construction Materials3 E 105 Practice for Probability Sampling of Materials4 E 177Practice for Use of the Terms Precision and Bias in ASTM Test Methods4 E 178 Practice for Dealing with Outlying Observations4 3. Significance and Use 3.1 Certain criteria need to be met before undertaking an interlaboratory study to determine the precision of a test method. It is not necessary that all of the following conditions described be completely fulfilled in every case; however, if someconditions are not met or are met incompletely, the program will become more complicated and require more work
1 This practice is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates . This practice was developed jointly by ASTM Committee C01, C09, D04, and D18, and is endorsed by all four committees. Current edition approved May 10, 1996. Published July 1996. Originallypublished as C 802 – 74 T. Last previous edition C 802 – 94. 2 Annual Book of ASTM Standards, Vol 04.01. 3 Annual Book of ASTM Standards, Vol 04.02. 4 Annual Book of ASTM Standards, Vol 14.02.

and expense, or may result in impaired information. The recommendations outlined in this section are intended to ensure that the test method is free of technical difficulties to the greatest extent possiblebefore an expensive and timeconsuming interlaboratory study is undertaken. 3.1.1 The first requirement is the existence of a valid and well-written test method that has been developed in one competent laboratory (or by cooperative work in a small number of laboratories), and has been subjected to a screening procedure, or to ruggedness testing as described in Practice C 1067. As a result of thescreening procedure and some experience with the test method in the sponsoring laboratory and one or two others, a written version of the test method has been developed (but not necessarily published as a standard method) that describes the test procedure in terms that can easily be followed in any properly equipped laboratory. Conditions that affect the test results should be identified and theproper degree of control of those conditions should be specified in the description of the test procedure (see Note 1).
NOTE 1—The desired degree of control of conditions that affect test results may not always be practically achievable, and tolerances in the test method should recognize this fact. Variations in test results due to variations in such conditions contribute to the total variation...